The purpose of the present invention is to provide sophisticated AWB technologies. According to one aspect of the present invention, there is provided a technology for adjusting a white balance of a frame of image data including a plurality of color elements. This technology is characterized by comprising: dividing the frame into a plurality of blocks including a plurality of pixel data; judging, for each of all of or a part of the blocks, whether the block is likely to be grey or not, and; deciding gains for adjusting a white balance using the blocks judged as being likely to be grey.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An apparatus, comprising circuitry, wherein the circuitry is configured to: divide a frame of image data comprising red, green and blue color elements into a plurality of blocks including a plurality of pixel data; define a plurality of intensity ranges for the plurality of pixel data in a block, in which the intensity ranges are different with each other; judge, for each of the intensity ranges, whether the blocks are likely to be grey in the intensity range and to cumulate average values of colors of the blocks judged as being likely to be grey in the intensity range for the respective color elements where criteria for grey judgment are different for each intensity range and use the red, green and blue color elements; provide, for each of the red, green and blue color elements, variable weightings to the cumulated values for the different intensity ranges, and to mix the variably weighted cumulated values, and; decide the gains for adjusting a white balance based on the mixed variably weighted cumulated values for the respective red, green and blue color elements.
2. An apparatus according to claim 1 , comprising circuitry configured to check each of all of or a part of the blocks whether the block contains a saturated pixel or not, and to exclude the block containing a saturated pixel from calculations for deciding the gains for adjusting a white balance.
3. An apparatus according to claim 2 , comprising circuitry configured to check each of all of or a part of the blocks whether the block is adjacent to the block containing a saturated pixel or not, and to exclude the block adjacent to the block containing a saturated pixel from calculations for deciding the gains for adjusting a white balance.
4. An apparatus according to claim 1 , where the judgment whether the block is likely to be grey or not is contingent on whether one, or more of B/G, R/G, min(R,B)/G, and max(R,B)/G satisfy given criteria or not, where: R represents an average value of the red data in the block to be judged, G represents an average value of the green data in the block to be judged, B represents an average value of the blue data in the block to be judged, min(R,B)/G represents a value dividing a smaller one of the R and the B by the G, max(R,B)/G represents a value dividing a larger one of the R and the B by the G.
5. An apparatus according to claim 4 , where the criteria are decided based on one or more of histograms of the respective color elements and luminance of the whole frame, and average values of the respective color elements of the whole frame.
6. An apparatus according to claim 4 , where calculations for deciding the criteria do not use the block containing a saturated pixel and/or the block adjacent to the block containing a saturated pixel.
7. An apparatus according to claim 1 , comprising circuitry configured to apply weighting to an average value of the color element in the block judged as being likely to be grey with higher probability, and/or an average value of the color element in the block having higher intensity.
8. An apparatus according to claim 1 , comprising circuitry configured to apply weighting for the mixing based on the numbers of blocks judged as being likely to be grey in the respective intensity ranges, and/or representative intensity values of the respective intensity ranges.
9. An apparatus according to claim 1 , comprising circuitry configured to calculate average values of the respective color elements from the blocks that do not contain any saturated pixels and/or the blocks that are not adjacent to the blocks containing a saturated pixel, and to decide the gains for adjusting a white balance by taking those average values into account.
10. An apparatus according to claim 1 , comprising circuitry configured to define one, or more color temperatures for the grey judgment, and circuitry configured to judge whether the block is likely to be grey or not in the defined color temperatures.
11. An apparatus according to claim 10 , where the color temperatures are defined based on one or more of following measures: a measure regarding a difference of histograms between the different color elements, a measure regarding a variance of a hue histogram, a measure regarding averages of the respective color elements obtained from the blocks that do not contain any saturated pixels, and a measure regarding averages of the respective color elements obtained from the blocks having larger intensity.
12. An apparatus according to claim 10 , where the apparatus comprises a memory storing characteristic data regarding the spectral response of a sensor of the apparatus with regard to a standard light source, and the apparatus comprises circuitry configured to calculate, for each of the blocks, a deviance between the characteristic data at the defined color temperature and averages values of the respective color elements in the block, and circuitry configured to judge that the block is likely to be grey when the deviance is less than a predetermined value.
13. An apparatus according to claim 10 , comprising: circuitry configured to calculate a first set of average values, the first set of average values is a set of average values of the color components in the blocks judged as being likely to be grey, and; circuitry configured to decide the gains for adjusting a white balance based on the first set of average values.
14. An apparatus according to claim 13 , comprising circuitry configured to apply weighting for the calculation of the first set of average values based on the deviance and/or intensity with regard to the blocks.
15. An apparatus according to claim 13 , comprising, circuitry configured to take a first set of supplemental values into account in the decision of the gains for adjusting a white balance; the first set of supplemental values is a set of values regarding the color elements corresponding to a location on the Plank curve that has the shortest distance from a location corresponding to the defined color temperature and a location corresponding to a second set of average values; the second set of average values is a set of average values of the respective color components of the blocks that do not contain any saturated pixels and/or the blocks that are not adjacent to the block containing a saturated pixel.
16. An apparatus according to claim 13 , comprising circuitry configured to take a second set of supplemental values into account in the decision of the gains for adjusting a white balance; the second set of supplemental values are values regarding the color elements corresponding to a location on the Plank curve that has the shortest distance from a location corresponding to the first set of averages.
17. An apparatus according to claim 1 , wherein the plurality of intensity ranges comprise at least two overlapping intensity ranges.
18. An apparatus according to claim 1 , wherein at least a portion of the circuitry is provided by, a CPU.
19. An apparatus comprising: a block extractor configured to: divide a frame of image data comprising red, green and blue color elements into a plurality of blocks including a plurality of pixel data; and an automatic white balance analyzer configured to: define a plurality of intensity ranges for the plurality of pixel data in a block, in which the intensity ranges are different with each other; judge, for each of the intensity ranges, whether the blocks are likely to be grey in the intensity range and to cumulate average values of colors of the blocks judged as being likely to be grey in the intensity range for the respective color elements where criteria for grey judgment are different for each intensity range and use the red, green and blue color elements; provide, for each of the red, green and blue color elements, variable weightings to the cumulated values for the different intensity ranges, and to mix the variably weighted cumulated values, and; decide the gains for adjusting a white balance based on the mixed variably weighted cumulated values for the respective red, green and blue color elements.
20. An apparatus according to claim 19 wherein the automatic white balance analyzer is configured to check each of all of or a part of the blocks whether the block contains a saturated pixel or not, and to exclude the block containing a saturated pixel from calculations for deciding the gains for adjusting a white balance.
21. An apparatus according to claim 19 wherein the automatic white balance analyzer is configured to define one or more color temperatures for the grey judgment, and configured to judge whether the block is likely to be grey or not in the defined color temperatures.
22. A method, performed at an apparatus, comprising: dividing a frame of image data including red, green and blue color elements into a plurality of blocks including a plurality of pixel data; defining a plurality of intensity ranges for the plurality of pixel data in a block, in which the intensity ranges are different with each other; for each of the intensity ranges, judging whether the blocks are likely to be grey in the intensity range and cumulating average values of colors of the blocks judged as being likely to be grey in the intensity range for the respective color elements where criteria for grey judgment are different for each intensity range and use the red, green and blue color elements; for each of the red, green and blue color elements, providing variable weightings to the cumulated values for the different intensity ranges, and mixing the variably weighted cumulated values, and; deciding the gains for adjusting a white balance based on the mixed variably weighted cumulated values for the respective red, green and blue color elements.
23. A method, performed at an apparatus, according to claim 22 further comprising checking each of all of or a part of the blocks whether the block contains a saturated pixel or not, and excluding the block containing a saturated pixel from calculations for deciding the gains for adjusting a white balance.
24. A non-transitory physical entity embodying a computer program comprising computer program instruction that, when executed by at least one processor, enable an apparatus to perform: dividing a frame of image data including red, green and blue color elements into a plurality of blocks including a plurality of pixel data; defining a plurality of intensity ranges for the plurality of pixel data in a block, in which the intensity ranges are different with each other; for each of the intensity ranges, judging whether the blocks are likely to be grey in the intensity range and cumulating average values of colors of the blocks judged as being likely to be grey in the intensity range for the respective color elements where criteria for grey judgment are different for each intensity range and use the red, green and blue color elements; for each of the red, green and blue color elements, providing variable weightings to the cumulated values for the different intensity ranges, and mixing the variably weighted cumulated values, and; deciding the gains for adjusting a white balance based on the mixed variably weighted cumulated values for the respective red, green and blue color elements.
25. A non-transitory physical entity according to claim 24 wherein the computer program instructions further enable the apparatus to check each of all of or a part of the blocks whether the block contains a saturated pixel or not, and to exclude the block containing a saturated pixel from calculations for deciding the gains for adjusting a white balance.
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August 28, 2006
January 27, 2015
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